The present invention relates to exchange method of mobile phase in high-performance liquid chromatography mass spectrometry and apparatus constituted in such a way that the mobile phase which can introduce mobile phases and components (containing substances) suitable for the components to be separated and to be partially taken into a mass spectrometer may be freely exchanged in high-performance liquid chromatography mass spectrometry.
The conventional high-performance liquid chromatography mass spectrometry has been performed as shown in FIG. 14. That is to say, (F.sub.0) is a container which has a mobile phase (L.sub.0) in it, (P.sub.0) is a pump, (IJ.sub.0) is an injector which injects a sample to be analyzed, (C.sub.0) is a separating column, (D.sub.0) is a detector, (MS.sub.0) is a mass spectrometer, and these are connected to each other by lines for sending liquid.
And, the apparatus is set up in such a way that the mobile phase (L.sub.0) which is sent by the pump (P.sub.0) as liquid is sent into the separating column (C.sub.0) together with the sample injected from the injector (IJ.sub.0). There components contained in the sample are separated into each component, and then introduced into the mass spectrometer (MS.sub.0). The presence of the components to be introduced into the mass spectrometer (MS.sub.0) can be previously detected by the detector (D.sub.0).
At the introducing part of the mass spectrometer (MS.sub.0), the mobile phase (L.sub.0) is first removed and simultaneously the aimed components are ionized and analyzed. However, there are several methods regarding the removing means and the ionizing means, and usable mobile phases and analyzable components are restricted by some methods.
These methods include, for example, Spray method (thermo-spray method, atmospheric spray method, particle beam method), frit FAB method, and the like.
However, the conventional method has the following troubles.
A. In case of the thermospray method, the presence of an electrolyte is indispensable to ionization, and it is necessary to use a buffer for the mobile phase in the high-performance liquid chromatography mass spectrometry. With regard to buffers to be used, however, when nonvolatile buffers such as phosphate buffer and the like are used, the buffer components are deposited on the metallic nozzle of the introducing part of the mass spectrometer, and use of the mass spectrometry becomes impossible. Accordingly, for the mobile phase in the high-performance liquid chromatography mass spectrometry the volatile buffers such as ammonium acetate and the like must be used, and as a result the components to be separated are extremely restricted.
B. In case of frit FAB method, matrix to be required for ionization, for example, glycerol, ethylenediamine and the like is added to the mobile phase; however, components to be separated are extremely restricted accordingly to the kind of matrix. Also, since the buffer used in the mobile phase enters directly the mass spectrometer, said buffer is restricted to such substance which are easy to ionize the aimed components, and components to be separated are extremely limited, similar to the thermo-spray method in the high-performance liquid chromatography mass spectrometry. Therefore, aimed components which can be separated by the high-performance liquid chromatography mass spectrometry are neutral substances which can be separated without using buffers in the mobile phase or a part of ionic components (acidic or basic compounds) which can be separated in the mobile phase of volatile buffers such as ammonium acetate. Thus, the aimed components are extremely restricted. Especially, compounds used in medicines include comparatively many kinds of ionic compounds, and therefore the conventional high-performance liquid chromatography mass spectrometry can not often cope with them.